From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D20D1C433E6 for ; Mon, 1 Feb 2021 11:53:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 719BC64E8F for ; Mon, 1 Feb 2021 11:53:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230124AbhBALxA (ORCPT ); Mon, 1 Feb 2021 06:53:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51446 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229495AbhBALw7 (ORCPT ); Mon, 1 Feb 2021 06:52:59 -0500 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E0874C061573 for ; Mon, 1 Feb 2021 03:52:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=DFvEMuSmJTMwKrx37KZALAZlQNbzmwOQTAjJ5KIsmrw=; b=w8cvjP/EhS0PSzIPxW+VuBQ9mb TZNQ7dWwgSY6NA0ZJzbMQK6Ku1B2KLt6pqyzZ16Bw1txT58zsTw7Ni3J459la9y5DYgKtNxTVmjyo YUgjsCd7fg6FJ67kJFf80vej3f4ZFRlLieWTI74UD6BVEXKpeGP1XG03NP6MH1MCL+ilraOrakuJl x1dNXJMRx+BR604fYQUQJfEZ1Q84nXFh7f+XKp3wdr2ExO7Tw9AQ36LdJ0z0Wxs+ovIQ5UtmUMquN +jbZ74Xwlo+ObX9Ain6ZPLDiMmMS94XtxKFzz2oC8cueQNZw1+LgT9gWroaPexBgFc9m9QARKLmR3 AV0epSdQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1l6XkX-00035y-Bm; Mon, 01 Feb 2021 11:52:09 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id AE3CA3011FE; Mon, 1 Feb 2021 12:52:07 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 98E9121A2F1E2; Mon, 1 Feb 2021 12:52:07 +0100 (CET) Date: Mon, 1 Feb 2021 12:52:07 +0100 From: Peter Zijlstra To: Nadav Amit Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Nadav Amit , Andrea Arcangeli , Andrew Morton , Andy Lutomirski , Dave Hansen , Thomas Gleixner , Will Deacon , Yu Zhao , Nick Piggin , x86@kernel.org Subject: Re: [RFC 08/20] mm: store completed TLB generation Message-ID: References: <20210131001132.3368247-1-namit@vmware.com> <20210131001132.3368247-9-namit@vmware.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210131001132.3368247-9-namit@vmware.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 30, 2021 at 04:11:20PM -0800, Nadav Amit wrote: > +static inline void tlb_update_generation(atomic64_t *gen, u64 new_gen) > +{ > + u64 cur_gen = atomic64_read(gen); > + > + while (cur_gen < new_gen) { > + u64 old_gen = atomic64_cmpxchg(gen, cur_gen, new_gen); > + > + /* Check if we succeeded in the cmpxchg */ > + if (likely(cur_gen == old_gen)) > + break; > + > + cur_gen = old_gen; > + }; > +} u64 cur_gen = atomic64_read(gen); while (cur_gen < new_gen && !atomic64_try_cmpxchg(gen, &cur_gen, new_gen)) ;